A junction box or bussed electrical center (BEC) is typically used in automotive vehicles to streamline electrical wiring by eliminating multi-branch wiring. The BEC enables branch circuits, fuses, relays and other electrical circuit components to be consolidated in a single housing and connected by wire harnesses to electrical devices and systems on the vehicle. The BEC housing is usually located in the vehicle engine compartment. The BEC typically has a lower "cover" or housing mounted in the engine compartment via pre-molded mounting points such as bolt receiving tabs or pads. The BEC itself is placed in the prior-mounted lower cover.
The BEC cover is often intricately molded, with a multi-faceted, curved, angled, and irregular outer surface to accommodate the usually cramped mounting location in the vehicle engine compartment. The cover also tends to be heavy, with thick, substantially rigid plastic walls, often weighing several pounds.
BEC covers often include tab type bolt mounting points, and a "base point" intended to be attached directly to a vehicle mounting surface. Prior art base points are typically bolt apertures through a portion of the BEC cover whose outer surface is adapted to be secured directly against a vehicle mounting surface. The fixed base point is intended to be secured to non-tolerance portions of a vehicle, such as a shock tower, where variation in the position of a vehicle mounting surface is not a concern. In the event of base point variations, the tab type mounting points are made thin enough and flexible enough to dampen vibration and adjust somewhat to tolerance problems at the base point. However, subjected over time to vibration, upper flex points thin enough to accommodate base point tolerances tend to break.
In newer vehicles, sheet metal now forms part of the "unibody" structural frame, often comprising several overlapping layers of welded sheet metal. This results in significant dimensional tolerances at the traditional base point mounting surface for BEC covers. Because the BEC cover is heavy, the two fixed top mounting tabs are not enough to handle the vibration resulting from any gap or spacing between the BEC cover base point and its vehicle mounting surface.